ここに　サービスは　9月17日までと　ありますね。

https://www.nps.gov/katm/planyourvisit/hours.htm

The park and preserve are open year-round. Most visitors arrive between June and October, when transportation and guiding services are readily available.

At Brooks Camp, National Park Service and concessioner services are offered from June 1 through September 17. Prime bear viewing months at Brooks Camp are July and September, although a few bears may be in the area at any time between late May and December.

じゃあ　9月18日から10月あたりまでに来る人たちは　たぶん　食料自分でもってくるか（なんか熊にとられそう）、アンカレッジからの飛行機のツアーでしょう。